1. Field of the Invention
This invention relates to accessory faucets, or so-called "third faucets", which are installed on the sink top adjacent to the conventional hot and cold water faucets. A third faucet is used to provide purified water for drinking when the usual household water is not suitable or desirable for drinking purposes. More specifically, the invention relates to a third faucet which is "vented"; that is, the outlet from the faucet valve is conducted back away from the faucet to the purifier or filter and from the purifier back to the faucet and out the faucet spout. Thus the invention relates to a "vented" faucet system.
2. Description of Related Art including Information Disclosed under .sctn..sctn.1.97 to 1.99
In the usual type of purified water system used with third faucets the filter is usually installed in the line between the water source and the third faucet. This means that the structure of the filter is subjected to household water pressure which may reach up into the neighborhood of 100 psi or more. Because of this the filter chamber and the fittings thereto must be designed to withstand such pressure without rupture or leakage. This requires heavy duty design with substantial fittings and wall thicknesses and has added to the cost of the filter. At the same time, because the filter is subjected to household pressure at all times, the cleaning or replacement of the filter has required shutting down the water supply to the filter, an inconvenience, unnecessary and undesirable.
In the prior art there are showings somewhat comparable to the present system. See, for instance, U.S. Pat. No. 4,210,533 to Astl issued Jul. 1, 1980. Also, my assignee's own U.S. Pat. No. 4,345,719 issued Aug. 24, 1982 and U.S. Pat. No. 4,537,360 issued Aug. 27, 1985 to Bock and my pending application Ser. No. 07/525,069 filed May 18, 1990 (my file WPM-2-D).